Actually take passed in args into consideration
Link feed pages to signup page

This also removes the database field and associated tests, as links are
built dynamically now.
Surface policies on signup form

Also include redirection and feed title helpers.
Hide feed/email URLs when calling out to Ajax

The URLs will change as soon as the call returns, so better to hide them
while in progress.
Merge pull request #505 from alphagov/local-email-alert-signups

Sign up to email alerts from anywhere

https://www.pivotaltracker.com/story/show/48590425